The present invention is directed to supplemental spine fixation devices and methods which are used as an adjunct to a primary spine fusion device, such as by way of example only, an interbody fusion device.
A common procedure for handling pain associated with degenerative spinal disk disease is the use of devices for fusing together two or more adjacent vertebral bodies. The procedure is known by a number of terms, one of which is interbody fusion. Interbody fusion can be accomplished through the use of a number of devices and methods known in the art. These include screw arrangements, solid bone implant methodologies, and fusion devices which include a cage or other mechanism which is packed with bone and/or bone growth inducing substances. All of the above are implanted between adjacent vertebral bodies in order to fuse the vertebral bodies together, alleviating associated pain.
Associated with such primary fusion devices and methods are supplemental devices which assist in the fusion process. These supplemental devices assist during the several month period when bone from the adjacent vertebral bodies is growing together through the primary fusion device in order to fuse the adjacent vertebral bodies. During this period it is advantageous to have the vertebral bodies held immobile with respect to each other so that sufficient bone growth can be established.
Such supplemental devices can include hook and rod arrangements, screw arrangements, and a number of other devices which include straps, wires, and bands, all of which are used to immobilize one portion of the spine relative to another.
All of these devices generally require extensive surgical procedures in addition to the extensive procedure surrounding the primary fusion implant.
It would be advantageous if the device and procedure for supplemental spine fixation were as simple and easy to perform as possible, and would leave intact all bone, ligament, and other tissue which comprise and surround the spine.
Accordingly, there needs to be developed procedures and implants which are minimally invasive and are supplemental to spine fixation devices and methods.
The present invention is directed to providing a minimally invasive supplemental spine fixation implant and method for alleviating discomfort associated with the spine.
The present invention provides for a method and apparatus for assisting in the fusing together of vertebral bodies of the spine. One of the features and purposes of the invention is to immobilize the vertebral bodies while spine fusion is accomplished. Generally fusion requires upwards of six months for bone cells from the upper and lower vertebral bodies to grow towards each other, generally through a primary fusion device.
In order to assist in the fusing process, the supplemental spinal fixation device and method of the invention immobilizes the vertebral bodies by immobilizing the respective spinous processes extending therefrom. In addition, the present invention and method can be used to distract apart the posterior sides of the vertebral bodies in order to put additional force and compression on the anterior sides of the vertebral bodies, further assisting in the interbody fusion process.
The present invention and method is minimally invasive such that it does not add to the trauma of the primary fusion procedure, especially if the fusion procedure is from a posterior approach. With an anterior fusion approach additional posterior incisions are required. However, these are minimal when compared to other devices and methods.
Accordingly an object of the present invention is to increase the rigidity and stability with respect to the adjacent spinous process and vertebral bodies in order to promote interbody fusion between the vertebral bodies.
It is further an object of the present invention to be as minimally invasive as possible.
It is yet a further object of the present invention to provide for an implant and method which does not require modification of the bone, ligaments, or adjoining tissues. In other words, it is an object of the present invention to provide for an implant and method which does not require that the bone be reshaped, notched, or in any way modified. Further it is an object of the present invention to provide for an implant and method which does not require that any of the ligaments associated with the spinous processes be altered.
It is a further object of the present invention to provide for an implant and method which can be inserted from one side of adjacent spinous processes, in order to immobilize the spinous processes and resultingly immobilize the adjacent vertebral bodies. By addressing the spinous processes from one side, the objects and advantages of a minimally invasive procedure, with reduced trauma, can be accomplished.
It is another object of the present invention to provide for a device and method which provides for distraction of the spinous processes in order to place pressure on at least the anterior portion of the vertebral bodies in order to assist in the primary fusion.
It is still a further object of the present invention to provide for an implant and method which can increase the space between spinous processes in order to adjust the height between vertebral bodies.
It is yet a further object of the present invention to provide for a device which has securing and/or hook elements which can easily and conveniently be secured about the spinous processes, which hook devices are preferably designed in order to accommodate the shape of the spinous processes and are preferably swivelable or pivotable in order to accommodate the position and shape of one spinous processes relative to another.
It is another object of the invention to provide for a device which has several degrees of freedom in order to allow a portion of the device to be positioned between spinous processes in order to distract apart the spinous processes and other portions of the device to engage the spinous processes in order to rigidly immobilize the spinous processes. These degrees of freedom allow the device to conform to the bones, ligaments, and tissues of each individual patient. Thus, the present device allows for adjustments along two and three axises in order to successfully distract and immobilize spinous processes.
It is yet a further object of the present invention to have at least one portion of the device selectably positionable with respect to other portions of the device in order to accommodate the anatomy of the spine and in particular of the spinous processes.
It is still a further object of the present invention to provide for a device and method which can be used with both primary anterior or posterior interbody fusion.
Accordingly, it is an object and aspect of the invention to provide a device and method for augmentation of single or multiple level lumbar spinal fusion. Ideally the fusion and the device and method of this invention are addressed at the L4/L5 vertebral bodies and above, and also at the L5/S1 vertebral bodies. The device and method can also be used with other vertebral bodies located along the spine.
The present invention provides for rigidity without risk to the neural elements. The present invention is cost effective and minimally invasive.
Accordingly, an aspect of the present invention includes an implant for rigidly positioning spinous processes, which implant includes a first means adapted for engaging the first spinous process and a second means adapted for engaging the second spinous process. The implant includes a body means adapted for positioning between the first spinous process and the second spinous process and a hub means for engaging the first means, the second means, and the body means.
Further, the invention includes at least one of the hub means and the body means allowing for the body means to move relative to at least one of the first and second means.
In a further aspect and object of the present invention, an implant includes a first hook adapted to engage a first spinous process and a second hook adapted to engage a second spinous process. The implant has a body adapted to the position between the spinous processes and a hub to which mounts the first and second hooks and the body. The body is moveable relative to at least one of the first and second hooks.
It is further an aspect and object of the present invention to provide an implant for rigidly positioning spinous processes as an adjunct to spine fusion, where the improvement includes a sleeve position between adjacent spinous processes.
It is a further aspect of the present invention to provide an implant for rigidly positioning spinous processes as an adjunct to spine fusion wherein the improvement comprises a sleeve or spacer positioned between adjacent spinous processes and a first hook which is adapted to engage a first spinous process and a second hook which is adapted to engage a second spinous process.
The method of the present invention is for rigidly positioning a first spinous process relative to a second spinous process and includes the steps in any desired order of placing a first hook around a first spinous process and a second hook around a second spinous process. The steps include placing a sleeve or spacer between the first and second spinous processes, which spacer mounts to a hub. The hub is used to interlock the first hook relative to the second hook.
Other embodiments of the implants and methods, within the spirit and scope of the invention, can be used to increase the volume of the spinal canal thereby alleviating restrictions on vessels and nerves associated therewith, and accordingly thereby alleviating pain.